Photographic developing-tank.



J. E. THORNTON;

PHOTOGRAPHIG DEVELOPING TANK.

APPLIOATION FILED JUNE 28. 1909.

Patented Jan. 10, 1911.

INVENTOR:

WITNESSES:

W's? M I UNITED STATES PATENT OFFICE.

JOHN EDWARD THORNTON, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR T0 FIRE- PROOF FILM COMPANY, A CORPORATION OF MAINE.

PHOTOGRAPHIC DEVELOPINGFTANK.

To all whom it may concern:

Be it known that I, JOHN EDWARD THoRN-. TON, a subject of the King of Great Britain, and resident of Philadelphia, in the county sary, to know the temperature of the developin solution'contained in the developing tan k in order that the operator may accurately determine the lengthof time the plates or films should be treated to complete the process of development without inspecting them during the progress of the operation. Hitherto it has been the usual practice to note the temperature of the room in which development is carried on, or else to immerse a thermometer in the liquid, and

then, after removal of the same, to place the plates or films in the tank and secure the lid thereon. This method is not accurate because the plates or' films may alter the temperature of the solution when immersed, and moreover it is not very convenient.

By this invention a thermometer is combined with the photographic developing tank and so fitted or connected thereto that the stem or tube will be outside and thetemperature of the developer contained in the tank can be ascertained at any time during the development.

This invention will be fully described with reference to the accompanying drawings in which as examples two forms of photographic development tanks are illustrated, it being understood that the invention may be applled to other of the various forms of photographic washing or developing tanks at present well known.

In the drawings :Figure 1 is a vertical section of one form of tank with the invention applied thereto; Fig. 2 is a vertical section of a modified form of attachment for the thermometer; Fig. 3 is a perspective view of another form of tank with the thermometer applied thereto in the manner of Fig. 2

T e photographic developing tank A in- Fig. 1 is made with a vertical recess or groove 0. with holes a at both bottom and Specification of Letters Patent. k Patented Jan. 10, I911.

top thereof through which a straight thermometer B is inserted, the recess being of such a length that the bulb b of the thermometer and the upper end of the stem remain within the interior of the tank. The holes a are sealed after the thermometer is inserted' Another form of photographic developing tank A is, shown in Figs. 2 and 8. The tank is constructed with a vertical slit 0: in one side and the thermometer B is mounted in a support or bracket D with a recess cl to receive the thermometer A and a flange around it by which to secure it to the tank. The

thermometer passes through holes d top and bottom, and is inserted into the interlor of the tank through the vertical slit. In a metal tank as shown, the flan e d issoldered to the side of the tank, bu? if the tank tangular box for film packs, or a square .or.

rectangular box provided with fixed grooves for plates.

The thermometer B may be charged with "mercury, colored spirit, or other suitable fluid and the gradations may be inscribed on the glass or stamped on the side of the tank or on a scale attached thereto.

What I claim is .1. A photographic developing tank having a depression in its wall providing a straight external recess, and having openings at the. ends of said recess through the wall, and a straight thermometer lying in said recess with its ends projecting through said openings into the interior of the tank.

is made of pot or other material, it may be 2. A photographic. developing tank comcess with its ends projecting through said prising a body provided with an elongated openings into the interior of the tank.

opening in its well, and a plate of sheetmetal closing said opening and having a. de- JOHN EDWARD THORNTON 5 pres'sion providing a straight external re- Witnesses:

cess, and o enings at the ends of said recess, ERNEST RInBn N,

and a stmlght thermometenlying in the re- WARREN N. 

